Many pesticides require the addition of an adjuvant to the spray mixture to provide wetting and penetrating effects on foliar surfaces. Often that adjuvant is a surfactant, which can perform a variety of functions, such as increasing spray droplet retention on difficult to wet leaf surfaces, or to provide penetration of the herbicide into the plant cuticle. These adjuvants are either provided as a component in an adjuvant formulation or used as an additive in herbicide formulations.
The addition to formulations of certain auxiliaries in order to improve the activity is generally known and agricultural practice. This has the advantage that the amounts of active ingredient in the formulation may be reduced while maintaining the activity of the later, thus allowing costs to be kept as low as possible and any official regulations to be followed. In individual cases it is also possible to widen the spectrum of action since plants, where the treatment with a particular active ingredient without addition was insufficiently successful, can indeed be treated successfully by the addition of certain auxiliaries. Moreover, the performance may be increased in individual cases by a suitable formulation when the environmental conditions are not favorable. The phenomenon that various active ingredients are not compatible with each other in a formulation can therefore also be avoided.
Such auxiliaries are generally also referred to as adjuvants. Frequently, they take the form of surface-active or salt-like compounds. Depending on their mode of action, they can roughly be classified as modifiers, activators, fertilizers, pH buffers and the like. Modifiers affect the wetting, sticking and spreading properties of a formulation. Activators break up the waxy cuticle of the plant and improve the penetration of the active ingredient into the cuticle, both short-term (over minutes) and long-term (over hours). Fertilizers such as ammonium sulfate, ammonium nitrate or urea improve the absorption and solubility of the active ingredient and may reduce the antagonistic behavior of active ingredients. pH buffers are conventionally used for bringing the formulation to an optimal pH.
Regarding the uptake of the active ingredient into the leaf, surface-active substances may act as modifiers and activator. In general, it is assumed that suitable surface-active substances can increase the effective contact area of liquids on leaves by reducing the surface tension. Moreover, surface-active substances can dissolve or break up the epicuticular waxes, thereby facilitating the absorption of the active ingredient. Furthermore, some surface-active substances can also improve the solubility of active ingredients in formulations and thus avoid, or at least delay, crystallization. Finally, they can also affect the absorption of active ingredients in some cases by retaining moisture. Surfactant-type adjuvants are exploited in a number of ways for agro-technical applications. They can be divided into groups of anionic, cationic, nonionic or amphoteric substances.
Substances which are traditionally used as activating adjuvants are petroleum-based oils. More recently, seed extracts, natural oils and their derivatives, for example of soybeans, sunflowers and coconut, have also been employed. However, it is a state of art to choose the right surfactant or surfactant blends to achieve the maximum adjuvancy for the pesticides.
It is therefore an object of the present invention to provide further uses of such adjuvant blends which have increased the pesticide efficacy more than any of the individual components can provide. We have found that this object is achieved by using the blend of alkoxylates and alkyl amines, salts, and quaternary salts as adjuvant and by providing agro-technical compositions comprising these blends.
The present invention therefore relates to the use of the blend of surfactants as adjuvant in the treatment of plants.